First, "this psychology professor" is trying to get people not to misuse his work, as reading the article would have told you. He is, in fact, "the scientific research". The reason he's not doing research now, as you seem to be asserting, is that he is retired. From doing research, you see.

Secondly, if you don't believe in psychopathy, you clearly haven't met my mother-in-law. (And I only wish I were joking.)